Bumping gaia.json for 2 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/542b91f91ac4
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #14074 from bebef1987/fix_contacts

Bug 943441 - test_import_contacts_from_gmail is failing on master for th...

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https://hg.mozilla.org/integration/gaia-central/rev/db71f8dc20e8
Author: Bebe <bebe@mozilla.ro>
Desc: Bug 943441 - test_import_contacts_from_gmail is failing on master for the wrong reason